This section provides background information related to the present disclosure which is not necessarily prior art.
Hand held power tools, such as drills and drivers, may include a housing and a handle attached thereto. Typically, the handle is a single stick-type handle that has a butt face attachment to the housing. This attachment results in a small footprint or mounting area for the handle on the housing. The power tool can generate high torque. The small footprint or mounting area for the handle on the housing can limit the distribution of the loading due to the high torque. Additionally, the power tool can be heavy and, being handheld, can be subject to being dropped. When dropped, the power tool may land on the handle or at an angle relative to the handle such that a large bending moment can occur at the location of the attachment of the handle to the housing. As stated above, the small footprint or mounting area, however, limits the ability of the handle to distribute the load and reduce the load concentration. As a result, the power tools can be subject to having the handle break when the power tool is subjected to large torque loading and/or dropped. Breaking the handle can make the power tool useless until a replacement handle is attached. Additionally, the need to purchase replacement handles increases the cost of ownership of the power tool. Thus, it would be advantageous if the handle loading could be spread out along a greater portion of the housing to reduce the stress concentrations during use and/or when the power tool is dropped to reduce the chance of the handle breaking. Additionally, the spreading of the stresses may also allow the use of different materials which may be more economical.
The power tools, such as drills or drivers, may generate large amounts of torque. As a result, when using the power tool, strong and violent forces may be incurred when the tool encounters an obstruction. For example, if a large diameter bit catches a nail or knot, the high torque produced by the power tool can cause it to rotate about the chuck axis. The operator may resist the rotation by holding onto the handle, or bracing it against a solid object. As a result, a large bending moment can occur at the location of the attachment of the handle to the housing due to the high torque. Additionally, when the power tool is a drill and a ship auger bit is being utilized, the auger bit can catch on a nail or similar feature, such as a knot. When this occurs, instead of the auger bit drilling through the material, it becomes a screw and can pull the power tool at a rapid pace toward the work piece. The handle, however, may not afford protection for the hand of a user. Additionally, the user's hand could possibly become trapped against the trigger and the work piece, thereby preventing the release of the trigger and de-energization of the power tool. As a result, the user may need to wait until the motor burns up or the power tool may need to be unplugged to de-energize the motor and allow the user to remove their trapped hand. Thus, it would be advantageous if the handle included features that distributed the load due to the high torque and/or to protect the user's hand. Additionally, it would be advantageous if the handle facilitated the allowing of a user to release the trigger regardless of the tool being trapped against a work piece.
In some power tools, it may be desirable to position sensors that relate to operation of the power tool at a position remote from the working bit. Thus, it would be advantageous to provide a power tool that provides various options for mounting of electronics or sensors therein to facilitate the operation of the sensor and control of the power tool.
The power tools may include an optional handle that can be attached to the housing at a location remote from the main handle. The optional handles can include a bail handle which is generally U-shaped and has ends that are attached to opposite sides of the housing. Additionally, a side handle can also be provided that projects outwardly from the housing and may be perpendicular to the housing. Typically, the housing includes two separate mounting holes on each side of the housing to attach the handles. One set of mounting holes are utilized to attach the bail handle on both sides of the housing, while the other set of holes is utilized to attach the side handle to either side of the housing. The two sets of mounting holes in the housing are machined holes that may be drilled and tapped during the manufacture of the housing. The use of two sets of mounting holes on each side, however, occupies space on the power tool and can interfere with the internal parts of the power tool, such as the transmission. As a result, the ability to provide a compact power tool can be limited by the necessity of having two sets of mounting holes in the housing. Additionally, machining of two separate holes on each side results in multiple machine operations and also takes time to produce the housing. It would be advantageous if the handles could utilize a single set of machined holes on either side of the housing which can thereby facilitate a more compact power tool and/or reduce the machining requirements and the costs and which may increase the manufacturing throughput.